Many of the genes that must function correctly to prevent disease in humans are also found in Drosophila. In many cases, a family of related genes in humans is represented by only a single ortholog in Drosophila. This streamlined genome and simple, rapid, sophisticated and inexpensive toolbox of techniques make Drosophila a very important model system.[unreadable] [unreadable] Multiple Endocrine Neoplasia Type 1 (MEN1) is an autosomal dominant cancer syndrome characterized by tumors of the endocrine tissues. These tumors proliferate slowly, but produce excessive amounts of hormones, such as insulin, which severely disrupts physiology in patents. MEN1 encodes Menin; a poorly understood protein that has been shown to interact with the transcription factor JunD. We examined the effect of loss-of-function and gain-of-function alleles of Drosophila Menin and demonstrated complex genetic interactions between Menin and Jun. Our data support the idea that Menin activity is highly dependent on cellular context.